#nav {
    height: 100px;
    line-height: 100px;
    background-color: rgba(0,0,0,0.1);
    #nav-box {
        height: 100%;
        width: 100%;
        overflow: hidden;
        li {
            text-align: center;
            width: 25%;
            float: left;
        }
    }
}

.center {
    // color: blue;
    text-align: center;
    font-size: 40px;
    width: 100%;
    height: 100%;
    position: absolute;
    left: 0;
    top: 400px;
}